Investigations of various geological phenomena including volcanos and earthquakes, involves precise measurement of tilting of the earths surface. A tilt meter such as a curved glass tube containing liquid and a gas bubble, can be supported in a close-to-horizontal position by mounting it on equipment that rests on a rock or other surface of the earth. While tilt sensors of only moderate costs are available for measuring tilt with extreme precision such as 10.sup.-7 radians such precision can be masked by tilting caused by thermal expansion and contraction of the mounting equipment. Such thermal expansion and contraction can be minimized by constructing the mounting equipment of material having an extremely low thermal coefficient of expansion (tce). However, such materials typically are very hard to machine to the required shapes, and their extensive use in the mounting equipment can greatly increase its costs. In many investigations, large numbers of tilt measuring installations are used, and it is desireable that the mounting equipment be of moderate cost.